1. Field of the Invention
The present invention is useful in the mineral resources industry as a method of reagent treatment of a well which is used for the recovery of any mineral resources (hydrocarbons; drinking, thermal and industrial water; or mineralized solutions) from the productive zone. This method involves the removal of clogging materials and the increase of the permeability of the rocks which make up the productive zone.
2. Prior Art
In industry practice, many methods of reagent treatment of wells are known which involve the injection of solutions of acid, alkali, and mixtures of salts of various acids, that react with the rocks and clogging material of different origins. See for example Sydansk (U.S. Pat. No. 4,280,560), Holtmyer (U.S. Pat. No. 4,519,455), McMillen (U.S. Pat. No. 4,531,586), Le Ribault (U.S. Pat. No 4,553,597), McMillen (U.S. Pat. No. 4,560,003), Knox (U.S. Pat. No. 3,374,835) and Slusser (U.S. Pat. No. 3,915,223).
Physio-chemical methods of maintaining reservoir pressure, based on the injection of various solutions into the reservoir (acid, alkali, polymer, surfactant and others), are widely used for increasing oil recovery from the productive horizon during the later stages of production of the field. In Peru (U.S. Pat. No. 4,817,715), a solution of sodium bicarbonate with a 0.25 percent to 5 percent concentration is injected in the layer through an injection well and the displaced oil is recovered from a well located nearby.
In order to increase oil recovery in Reisberg (U.S. Pat. No. 3,111,985), an acidic napthene solution based on kerosene is injected into the reservoir, followed by the injection of a sodium hydroxide solution in a concentration of 0.1 percent. This solution neutralizes the acidic solution and acts as a displacement agent.
Polymictic gel, used in Elphingstone et al. (U.S. Pat. No. 4,215,001), and having thixotropic properties, is injected in the layer to react on the fractures of the near-well zone. This gel is prepared by mixing acidic solutions based on hydrochloric, phosphoric and sulfuric acid or their mixture with sodium oxide and silicium.
Gomory et al (U.S. Pat. No. 4,541,488) is used for the dissolution of calcium and iron clogging compounds in the perforated zone of water wells. A weak acidic solution (acetic, tartaric, citric, metaboric, tetraboric) is injected into the layer and retained in the well for ten to 48 hours. After that, the weak acidic solution is pumped out of the well. Then a sodium bicarbonate and/or sodium hydrochloride solution is injected and retained for one to 36 hours. Thereafter, the well is flushed out.
However, none of the above-mentioned processes effectively reacts in the necessary measure on the argillaceous clogging materials of natural or external origin or on the permeability of the productive horizon.
The purpose of this invention is to develop a technology which permits a positive reaction on the clogging materials and on the permeability of the near-well zone causing an increase in the productivity of wells producing hydrocarbons, drinking, thermal and industrial water, mineralized and other solutions.